Adverse human health effects due to occupational and environmental exposure to nanomaterials are a major concern and a potential threat to their successful commercialization and biomedical applications. Realization of their commercial potential will require a better understanding of the interactions of nanomaterials with biological systems and the development of new strategies to manage human health risk. Toxicological screening is urgently needed to identify potentially hazardous nanomaterials;however their wide variability and unique properties complicate interpretation of traditional in vitro and in vivo toxicity assays. An interdisciplinary research team at Brown University including a materials scientist, a toxicologic pathologist, and a molecular biologist has developed a panel of novel nanomaterials and innovative approaches for nanotoxicology assays. This panel of model nanomaterials will be expanded to include selected commercial materials subjected to rigorous characterization of toxicologically relevant materials propertied. The goal of this competitive revision is to identify the specific structural and surface properties of carbon nanotubes responsible for the genotoxicity and potential carcinogenicity following inhalation. Novel imaging techniques at the light microscopic and ultrastructural levels will be used to study the interaction of fibrous nanomaterials with dividing cells. PUBLIC HEALTH RELEVANCE: This research will lead to rational material design strategies for manufacturing of carbon nanotubes with minimal adverse human health impact.